According to Cloudflare Rocket Loader's documentation, it prioritizes your website’s content (text, images, fonts, and more) by deferring the loading of all of your JavaScript until after rendering.
This could cause a delay in loading our Convert Snippet and result in a noticeable flicker effect.
To avoid this, we recommend including the attribute data-cfasync="false" to our snippet.
For instance, if the snippet appears as follows:
<script type="text/javascript" src="//cdn-4.convertexperiments.com/js/12345678-12345678.js">
</script>
The updated snippet would look like this:
<script data-cfasync="false" type="text/javascript" src="//cdn-4.convertexperiments.com/js/12345678-12345678.js">
</script>
By doing so, Rocket Loader will ignore our Convert snippet while optimizing the loading of other scripts on the page, as per the Rocket Loader documentation:
https://developers.cloudflare.com/fundamentals/speed/rocket-loader/ignore-javascripts/